ped the burner under his arm and unscrewed the top of the
little bottle. He shook it.

Nothing happened.

"It's got a seal," Casker pointed out.

Hellman punctured the seal with his fingernail and set the bottle on
the floor. An evil-smelling green froth began to bubble out.

Hellman looked dubiously at the froth. It was congealing into a glob
and spreading over the floor.

"Yeast, perhaps," he said, gripping the burner tightly.

"Come, come. Faint heart never filled an empty stomach."

"I'm not holding _you_ back," Hellman said.

The glob swelled to the size of a man's head.

"How long is that supposed to go on?" Casker asked.

"Well," Hellman said, "it's advertised as a Plugger. I suppose that's
what it does--expands to plug up holes."

"Sure. But how _much_?"

"Unfortunately, I don't know how much two cubic vims are. But it can't
go on much--"

Belatedly, they noticed that the Plugger had filled almost a quarter
of the room and was showing no signs of stopping.

"We should have believed the label!" Casker yelled to him, across the
spreading glob. "It _is_ dangerous!"

As the Plugger produced more surface, it began to accelerate in its
growth. A sticky edge touched Hellman, and he jumped back.

"Watch out!"

He couldn't reach Casker, on the other side of the gigantic sphere of
blob. Hellman tried to run around, but the Plugger had spread, cutting
the room in half. It began to swell toward the walls.

"Run for it!" Hellman yelled, and rushed to the door behind him.

* * * * *

He flung it open just as the expanding glob reached him. On the other
side of the room, he heard a door slam shut. Hellman didn't wait any
longer. He sprinted through and slammed the door behind him.

He stood for a moment, panting, the burner in his hand. He hadn't
realized how weak he was. That sprint had cut his reserves of energy
dangerously close to the collapsing point. At least Casker had made
it, too, though.

But he was still in trouble.

The Plugger poured merrily through the blasted lock, into the room.
Hellman tried a practice shot on it, but the Plugger was evidently
impervious ... as, he realized, a good plugger should be.

It was showing no signs of fatigue.

Hellman hurried to the far wall. The door was locked, as the others
had been, so he burned out the lock and went through.

How far could the glob expand? How much was two cubic vims? Two cubic
miles, perhaps? For